This invention relates to methods for enhancing the distribution and penetration of wood preservatives into a wood substrate with a wood penetration enhancing agent comprising an amine oxide. This invention also relates to preservative compositions comprising a wood preservative selected from quaternary ammonium compounds, amines. and salts thereof and an amine oxide.
Current methods for treating wood with preservatives often do not provide uniform distribution and penetration of the preservatives into the wood. As a result, portions of the wood may decay while other portions remain well preserved.
Furthermore, wood preservatives frequently do not penetrate or poorly penetrate to the center of thick pieces of wood, such as posts, timbers, and boards. This often results in the wood rotting from the inside out. Wood preservatives typically preferentially absorb at certain locations or sites in the wood. Because of the lack of uniform distribution, certain locations of the wood do not receive the same wood preservative effect as other locations.
U.S. Pat. No. 5,833,741 discloses a waterproofing wood preservative system comprising a waterproofer and a biocide. The waterproofer is an alkyl amine oxide, an alkyl acetoacetate, or a waterproofing quaternary ammonium compound. The biocide comprises at least one specific biocidal quaternary ammonium compound.
U.S. Pat. No. 4,357,163 discloses a wood treating composition containing a chlorophenol, an aliphatic alcohol, a fatty acid amine oxide, and water.
There is a need for methods of enhancing the distribution and penetration of wood preservatives into wood in order to provide uniform distribution and penetration of the preservatives and to prevent decay in the inner and outer regions of the wood.
Applicants have discovered that amine oxides enhance the uniform distribution and penetration of wood preservatives into wood substrates, minimize leaching of the wood preservatives, and improve the weatherability of the wood substrate (i.e. improve the surface appearance of the wood, the wood""s resistance to cracking, splitting, pitting, and changing color). The present invention provides a method for enhancing the uniform distribution and penetration of at least one wood preservative into a wood substrate by applying a preservative composition to the wood substrate. The preservative composition comprises a wood distribution and penetration enhancing agent, which includes an amine oxide, and the wood preservatives.
Another embodiment of the present invention is a method for enhancing the uniform distribution and penetration of one or more wood preservatives by applying the wood preservatives to the wood substrate and then applying the aforementioned wood distribution and penetration enhancing agent to the wood substrate. Alternatively, the wood distribution and penetration enhancing agent may be applied prior to application of the wood preservatives or both may be applied concurrently.
Yet another embodiment is a preservative composition comprising a wood distribution and penetration enhancing agent and at least one wood preservative. Preferably, the composition comprises a uniform distribution and penetration enhancing effective amount of the wood distribution and penetration enhancing agent and a wood preserving effective amount of the wood preservative.
The present invention provides a method for enhancing the uniform distribution and penetration of at least one wood preservative into a wood substrate. The method comprises applying a preservative composition to the wood substrate. The preservative composition comprises a wood distribution and penetration enhancing agent and the wood preservative. The wood distribution and penetration agent includes one or more amine oxides.
The amine oxide may be a trialiphatic substituted amine oxide, an N-alkylated cyclicamine oxide, a dialkylpiperazine di-N-oxide, an alkyldi(hydroxylated oxyalkyl)amine oxide, a dialkylbenzylamine oxide, a fatty dimethylamido dimethylpropylamine oxide, a diamine oxide; a triamine oxide, or any combination of any of the foregoing. Examples of suitable amine oxides include, but are not limited to, alkyl, alkenyl or alkynyl amine oxides. Preferably, the amine oxide includes at least one C1-C18 alkyl moiety.
Preferred trialiphatic substituted amine oxides have the formula R1R2R3Nxe2x86x92O, where R1 is a linear, branched, cyclic or any combination thereof C6 to C40 saturated or unsaturated group; and R2 and R3 independently are linear, branched, or any combination thereof C1 to C40 saturated or unsaturated groups. R1, R2, and R3 independently may be alkyl, alkenyl, alkynyl, cycloalkyl, aryl, or any combination of any of the foregoing. More preferably, R1 is a linear, branched, cyclic or any combination thereof C6 to C22 saturated or unsaturated group, such as coco, hydrogenated tallow, soya, decyl, hexadecyl, and oleyl; and R2 and R3 independently are linear, branched, or any combination thereof C1 to C22 saturated or unsaturated groups, such as coco, hydrogenated tallowm, soya, decyl, and hexadecyl. According to a preferred embodiment, R1 is a linear or branched C6 to C14 saturated or unsaturated group.
A preferred trialiphatic substituted amine oxide is a dialkylmethylamine oxide having the formula R1R2CH3Nxe2x86x92O, where R1 and R2 are defined as above.
Another preferred trialkylamine oxide is an alkyldimethylamine oxide having the formula R1(CH3)2Nxe2x86x92O, where R1 is defined as above. Alkyldimethylamine oxides are non-toxic and non-mutagenic surfactants. More preferably, R1 is a C6-C22 saturated or unsaturated group. Preferred alkyldimethylamine oxides include, but are not limited to, decyldimethylamine oxide, dodecyldimethylamine oxide, tetradecyldimethylamine oxide, hexadecyldimethylamine oxide, coco-dimethylamine oxide, octadecyldimethylamine oxide, hydrogenated tallow dimethylamine oxide, and any combination of any of the foregoing.
Preferred N-alkylated cyclicamine oxides have the formula R4R5R6Nxe2x86x92O where R4 is defined as R1 above and R5 and R6 are linked to form a cyclic group. The cyclic group typically contains from 4 to 10 carbon atoms and may optionally contain oxygen, sulfur, nitrogen, or any combination of any of the foregoing. More preferred N-alkylated cyclicamine oxides include, but are not limited to, an alkylmorpholine N-oxide, a dialkylpiperazine di-N-oxide, and any combination of any of the foregoing.
Preferred alkylmorpholine N-oxides have the formula 
where R7 is defined as R1 above. According to a more preferred embodiment, R7 is a linear or branched C10 to C16 alkyl. Examples of preferred alkylmorpholine N-oxides include, but are not limited to, cetyl morpholine N-oxide and lauryl morpholine N-oxide.
Preferred dialkylpiperazine di-N-oxides have the formula 
where R8 is defined as R1 above and R9 is defined as R2 above.
Preferred alkyldi(hydroxyalkyl)amine oxides have the formula 
where R10 is defined as R1 above; R11 and R12 independently are H or CH3; and m and n independently are integers from 1 to 10.
Preferred dialkylbenzylamine oxides have the formula R13R14R15Nxe2x86x92O, where R13 is defined as R1 above; R14 is defined as R2 above; and R15 is benzyl. More preferred dialkylbenzylamine oxides include, but are not limited to, alkylbenzylmethylamine oxides having the formula R13R15CH3Nxe2x86x92O where R13 and R15 are defined as above. According to a more preferred embodiment, R13 is a linear or branched C8-C12 alkyl.
Preferred fatty dimethylamido dimethylpropylamine oxides have the formula 
where R16 is defined as R1 above.
Preferred diamine oxides have the formula 
where R17 is defined as R1 above; and m is an integer from about 1 to about 10.
Preferred triamine oxides have the formula 
where R18 is defined as R1 above; and m and n independently are integers from about 1 to about 10.
Long chain (C16 or greater) amine oxides, such as hexadecylamine oxides and hydrogenated tallow amine oxides, are particularly preferable for imparting waterproofing properties to the composition. Short chain (C14 and shorter) amine oxides are particularly efficient wood distribution and penetration enhancing agents and aide in solubilizing long chain amine oxides.
The wood preservative may comprise a quaternary ammonium compound, amine, or salt thereof. Suitable quaternary ammonium compounds include, but are not limited to, those having the formula R19R20R21R22N+Xxe2x88x92; where R19, R20, R21, and R22 independent are linear, branched, cyclic or any combination thereof saturated or unsaturated groups and X is an anion. The sum of the number of carbon atoms in R19, R20, R21, and R22 broadly ranges from about 10 to about 50. R19, R20, R21, and R22 may be alkyl, alkenyl, alkynyl, cycloalkyl, aryl, or any combination of any of the foregoing. X may be chloride, carbonate, bicarbonate, nitrile, bromide, iodide, acetate, dehydroacetate, laurate, stearate, carboxylate, or borate. Suitable carboxylate and borate anions include, but are not limited to, those disclosed in U.S. Pat. No. 5,641,726, which is hereby incorporated by reference.
A preferred quaternary ammonium compound has the formula R19(CH3)3N+Xxe2x88x92, where R19 is a linear or branched C10-C20 saturated or unsaturated group, such as alkyl, alkenyl, or alkynyl group and X is defined as above. More preferably R19 is a linear C16-C18 saturated or unsaturated group and X is chloride, carbonate, or acetate. An example of such a compound is N-octadecyl-N,N,N-trimethylammonium chloride.
Another preferred quaternary ammonium compound has the formula R19R20(CH3)2N+Xxe2x88x92, where R19 is a linear or branched C6-C20 saturated or unsaturated group or C6-C20 substituted or unsubstituted aryl group, R20 is a linear or branched C1-C20 saturated or unsaturated group or C6-C20 substituted or unsubstituted aryl group, and X is defined as above. The term xe2x80x9csubstitutedxe2x80x9d as used herein includes, but is not limited to, substitution with any one or any combination of the following substituents: C1-C4 alkyl. Preferably, R19 and R20 independently are linear or branched C8-C15 saturated or unsaturated groups. In a more preferred embodiment, R19 and R20 independently are linear or branched C8-C12 saturated or unsaturated groups and X is chloride, carbonate, or acetate. Special mention is made of didecyldimethylammonium chloride, which is available as Bardac(copyright) 2280 available from Lonza Inc. of Fair Lawn, N.J.; didecyldimethylammonium bicarbonate; and didecyldimethylammonium carbonate; and N,N-di(tetradecyl/pentadecyl)-N,N-dimethylammonium chloride, which is available as Carsoquat(copyright) 457 from Lonza Inc. (Carsoquat(copyright) 457 is a mixture of N-tetradecyl-N-pentadecyl-N,N-dimethylammonium chloride, N,N-di(tetradecyl)-N,N-dimethylammonium chloride, and N,N-di(pentadecyl)-N,N-dimethylammonium chloride).
Another suitable quaternary ammonium compound has the formula R19R20(CH3)2N+Xxe2x88x92), where R19 is a substituted or unsubstituted benzyl group, R20 is linear C10 to C20 saturated or unsaturated group, and X is defined as above. According to a preferred embodiment, R19 is benzyl, R20 is a linear C12-C18 saturated or unsaturated group, and X is chloride. Examples of such compounds include, but are not limited to, a mixture of Nxe2x80x94(C12-C16)alkyl-N-benzyl-N,N-dimethylammonium chloride, which is available as Barquat(copyright) MB from Lonza, Inc. of Fair Lawn, N.J.; and N-octadecyl-N-benzyl-N,N-dimethylammonium chloride, which is available as Carsoquat(copyright) SDQ from Lonza Inc.
Another quaternary ammonium compound contemplated for use in the present invention has the formula R19R20N+(CH3)(CH2CH2O)nH Xxe2x88x92 where R19 is a C6-C20 linea or branched, substituted or unsubstituted alkyl group or a C6-C20 substituted or unsubstituted aryl group, R20 is a C1-C20 linear or branched, substituted or unsubstituted alkyl group or a C6-C20 substituted or unsubstituted aryl group, n is an integer from 1 to 2, and X is defined as above. Preferably, R19 and R20 are linear or branched C8-C10 substituted or unsubstituted groups and more preferably are decyl. X is preferably propionate. An example of such a compound is N,N-didecyl-N-methyl-N-hydroxyethylammonium proprionate, available as Bardap(copyright) 26 from Lonza, Inc. of Fair Lawn, N.J.
Yet another suitable quaternary ammonium compound has the formula R19R20R21(CH3)N+Xxe2x88x92, where R19, R20, and R21 independently are linear or branched C6-C22 saturated or unsaturated groups. More preferably R19, R20, and R21 independently are linear or branched C8-C10 saturated or unsaturated groups. X is preferably chloride. Examples of such compounds include, but are not limited to, N,N,N-tri(octyl/decyl)-N-methylammonium chloride, which is available as Aliquat(copyright) 336 from Aldrich Chemical Company of Milwaukee, Wis. (Aliquat(copyright) 336 is a mixture of N,N,N-tri(octyl)-N-methylammonium chloride, N,N-di(octyl)-N-decyl-N-methylammonium chloride, N-octyl-N,N-di(decyl)-N-methylammonium chloride, and N,N,N-tri(decyl)-N-methylammonium chloride.
Suitable amines include, but are not limited to, those having the formula R23R24R25N, where R23, R24, and R25 independent are linear, branched, cyclic or any combination thereof saturated or unsaturated groups. The sum of the number of carbon atoms in R23, R24, and R25 broadly ranges from about 10 to about 50. R23, R24, and R25 may be alkyl, alkenyl, alkynyl, cycloalkyl, aryl, or any combination of any of the foregoing.
An amine contemplated for use in the present invention has the formula R23N(CH3)2 where R23 is a linear, branched, cyclic or any combination thereof C6-C30 saturated or unsaturated group or C6-C30 substituted or unsubstituted aryl group. R23 is preferably a linear and saturated C8-C20 group. Examples of such compounds include, but are not limited to, N-lauryl-N,N-dimethylamine, which is available as Barlene(copyright) 12C from Lonza Inc. of Fair Lawn, N.J.; N-dodecyl-N,N-dimethylamine, which is available as Barlene(copyright) 12S from Lonza Inc.; N-hexadecyl-N,N-dimethylamine, which is available as Barlene(copyright) 16S from Lonza Inc.; cocodimethylamine; N-octadecyl-N,N-dimethylamine, which is available as Barlene(copyright) 18S from Lonza Inc.; hydrogenated tallow dimethylamine; or any combination of any of the foregoing.
Suitable amine salts include, but are not limited to, any salts of the aforementioned amines. The salts may be formed with organic or inorganic acids. Any acid which reacts with the amine may be used. The amine salt may be partially or wholly neutralized by the acid. Preferred salts include, but are not limited to, acetates and dehydroacetates (DHA). The anion may also be any carboxylate or borate anion, such as those described in U.S. Pat. No. 5,641,726. For example, the amine salt may have the formula R26R27R28N+Yxe2x88x92, wherein R26, R27, and R28, are defined as R23, R24, and R25 above and Y is defined is X as above and any of the aforementioned anions, such as acetate and dehydroacetate. Another example is an amine salt having the formula R29(CH3)2N+Yxe2x88x92, wherein R29 is defined as R23 above and Y is any of the aforementioned anions.
The weight ratio of amine oxide to wood preservative in the preservative composition broadly ranges from about 1:10 to about 10:1 and preferably ranges from about 1:6 to about 4:1. Where waterproofing properties are desired, the weight ratio preferably ranges from about 1:1 to about 4:1.
The pH of the preservative composition broadly ranges from about 2 to about 12. The pH of the preservative composition preferably ranges from about 6 to about 8 and is more preferably about 7.
The preservative composition may further comprise water and/or other water compatible solvents, such as alcohols, glycols, ketones, and esters. Additionally, the preservative composition may contain other additives as known in the art. The preservative composition typically comprises a uniform distribution and penetration enhancing effective amount of the wood distribution and penetration enhancing agent and a wood preserving effective amount of the wood preservative. The preservative composition generally comprises from about 0.1 to about 10% by weight of amine oxides and from about 0.1 to about 10% by weight of wood preservatives, based on 100% total weight of preservative composition. The preservative composition preferably comprises from about 0.5 to about 4% by weight of amine oxides and from about 0.5 to about 4% by weight of wood preservatives, based on 100% total weight of preservative composition.
Suitable wood substrates include, but are not limited to, Ponderosa pine sapwood, southern yellow pine, and Scots pine.
The preservative composition may be applied to the wood substrate by any method known to one of ordinary skill in the art including, but not limited to, brushing, dipping, soaking, vacuum impregnation, and pressure treatment using various cycles.
Another embodiment is a method for enhancing the uniform distribution and penetration of one or more wood preservatives by applying the wood preservative to the wood substrate and then applying the aforementioned wood distribution and penetration enhancing agent to the wood substrate. A uniform distribution and penetration enhancing amount of the wood distribution and penetration enhancing agent and a wood preserving effective amount of the wood preservative are typically applied. The wood distribution and penetration enhancing agent is generally applied to the wood substrate as a solution containing from about 0.1 to about 10% and preferably from about 0.25 to about 4% by weight of amine oxide, based on 100% total weight of solution. The wood preservatives are also typically applied to the wood substrate as a solution containing from about 0.1 to about 10% and preferably about 0.25 to about 4% by weight of wood preservative, based on 100% total weight of solution. The solutions may contain water and/or other water compatible solvents as described above. The wood penetration enhancing agent and wood preservative may be applied by any of the aforementioned methods.
Alternatively, the wood distribution and penetration enhancing agent may be applied to the wood substrate after application of the wood preservative or both may be applied concurrently.